lit fiber
jargonISP & telecom
Fiber with the electronics attached and light flowing - a working service, as opposed to dark fiber you light yourself.
The buy-versus-build of the physical layer: lit service means the provider owns the optics and the wavelengths, dark fiber means you do. 'Lit building' is the sales version - the fiber is already there, turn-up is fast.
Also known as: lit fibre, lit service